ICS1893 datasheet(29/153 Pages) RENESAS

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Chapter 6

Interface Overviews

ICS1893 Rev C 6/6/00

June, 2000

ICS1893 - Release

6.3

10M Serial Interface

When the Mac/Repeater Interface is configured as a 10M Serial Interface, the ICS1893 and the

MAC/repeater exchange a framed, serial bit stream along with associated control signals. The 10M Serial

Interface configuration is ideally suited to applications that already incorporate a serial 10Base-T MAC with

a standard ‘7-wire’interface. The ICS1893 MAC/Repeater Interface can be configured for 10M Serial

Interface operations, as determined by ICS1893 configuration functions. When the HW/SW pin is set for:

• Hardware mode, the 10M Serial Interface is selected when both of the following are true:

– The MII/SI input pin is logic one (that is, the selection is for a Serial Interface).

– The 10/100SEL input pin is logic zero (that is, the selection is for 10M operations).

• Software mode, the 10M Serial Interface is selected when both of the following are true:

– The MII/SI input pin is logic one (that is, the selection is for a Serial Interface).

– The Control Register Data Rate bit (bit 0.13) is logic zero (that is, the selection is for 10M operations).

Note:

In software mode, the 10/100SEL pin becomes an output that indicates the state of bit 0.13.

A10M Serial Interface has two data paths: one for data transmission and one for data reception. Each data

path exchanges a serial bit stream with the MAC/repeater at a 10-MHz clock rate. A benefit of using the

10M Serial Interface – in contrast to the 10M MII Interface – is a reduction in the bit latency through the

ICS1893. This reduction is attributed to eliminating both parallel-to-serial and serial-to-parallel data

conversions.

The 10M Serial Interface consists of the following eight signals:

• 10COL

• 10CRS

• 10RCLK

• 10RD

• 10RXDV

• 10TCLK

• 10TD

• 10TXEN

When the ICS1893’s MAC/Repeater Interface is configured for 10M Serial operations, both its default MII

pin names and their associated functions are redefined. For more information, see Section 9.3.4.3,

“MAC/Repeater Interface Pins for 10M Serial Interface”.

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